React Native allows developers to build native applications for iOS and Android using components written in the React JavaScript framework. These ReactJS components render to native application code by going over a JavaScript bridge, a message bus that communicates between JavaScript code and native iOS or Android runtimes.

To address the performance issues of React Native, the core team working on React Native at Facebook is rearchitecting the React Native runtime within a project called Fabric. Fabric consists of changes to the threading model, the data handling system, and the JavaScript bridge.